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United States Patent |
5,530,551
|
Cantrall
,   et al.
|
June 25, 1996
|
Method for apparatus for determining measurement parameter of a fibrous
object and whether the object is a valid object
Abstract
Disclosed is a method/apparatus to determine any one of a plurality of
parameters: shape, area, chemical composition, diameter, color, number,
thickness, width, length, absorptivity, reflectivity, transmittivity,
dielectric constant, raman scattering profile, fluorescence, surface
tension, roughness, profile, density, position and orientation. Also use
of a plurality of energy beams as source energy: charged and neutral
particle beams, gamma-, X-, micro-, optical and acoustic waves. The
described apparatus determines the mean and standard deviation of a
plurality of diameters of wool fibers, and includes a He-Ne laser (101),
and a pinhole (102) which produce an expanding laser beam which passes
through cell (105). Beam splitter (103) is operatively disposed to pinhole
(102) and laser (101) to direct a portion of the laser beam to reference
detector (109) which is electrically connected to processor (110) via line
(111). When apparatus (100) is operating wool fibers in an
isopropanol-wool slurry pass through cell (105) generally at a non-zero
degree angle to the direction of slurry flow through cell (105) to
interact with the laser beam in cell (105 ). Beam splitter (104) and
microscope objective (106) are operatively disposed with respect to laser
(101), pinhole (102) and cell (105) to produce an in focus magnified
transmission image of wool fibers in cell (105) in the plane of end (107)
of optical fiber bundle (108). Each of the fibers in bundle (108) is
connected to a photodiode detector (112). Processor/timer (113) is
connected electrically to detector (112) by line (114). Processor/timer
(113) is also connected electrically to computer (115) by line (116) and
to processor (110) by line (117). Detector (118) is connected electrically
to processor (110) by line (119). Processor (110) is connected
electrically to computer (115) by line (120). Detector (118) is
operatively disposed with respect to laser (101), pinhole (102) and cell
(105) to detect outgoing light.
Inventors:
|
Cantrall; Chistopher J. (Normanhurst, AU);
Dabbs; Timothy P. (West Ryde, AU);
Glass; Monty (Dulwich Hill, AU);
Humphries; William (Narara, AU);
Wills; Leslie J. (Berala, AU)
|
Assignee:
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Commonwealth Scientific and Industrial Research (AU)
|
Appl. No.:
|
199298 |
Filed:
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March 2, 1994 |
PCT Filed:
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September 2, 1992
|
PCT NO:
|
PCT/AU92/00465
|
371 Date:
|
March 2, 1994
|
102(e) Date:
|
March 2, 1994
|
PCT PUB.NO.:
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WO93/05359 |
PCT PUB. Date:
|
March 18, 1993 |
Foreign Application Priority Data
Current U.S. Class: |
356/394; 356/335; 356/635 |
Intern'l Class: |
G01B 011/00 |
Field of Search: |
356/394,384,385,386,238,345,351,354,355,357,335-343
|
References Cited
U.S. Patent Documents
3518007 | Jun., 1970 | Ito | 356/357.
|
3643101 | Feb., 1972 | Shipp et al. | 356/384.
|
3680961 | Aug., 1972 | Rudd | 356/335.
|
3719425 | Mar., 1973 | Leitz et al. | 356/384.
|
3851169 | Nov., 1974 | Faxvog | 250/222.
|
4046536 | Sep., 1977 | Smithgall, Sr. | 356/385.
|
4053229 | Oct., 1977 | McCluney | 356/339.
|
4266874 | May., 1981 | Tanin et al. | 356/335.
|
4623252 | Nov., 1986 | Hollenbeck | 356/338.
|
4650322 | Mar., 1987 | Fejer et al. | 356/385.
|
4837446 | Jun., 1989 | Renard et al. | 250/461.
|
5161053 | Nov., 1992 | Dabbs | 359/384.
|
Foreign Patent Documents |
5786873 | Jan., 1975 | AU.
| |
5148579 | Apr., 1980 | AU.
| |
7484391 | Sep., 1991 | AU.
| |
0225009 | Jun., 1987 | EP.
| |
351436 | Jan., 1990 | EP.
| |
657554 | Sep., 1986 | CH.
| |
1067457 | May., 1967 | GB.
| |
1116009 | Jun., 1968 | GB.
| |
Other References
Patent Abstracts of Japan, vol. 16, No. 203, 14 May 1992, JP-A-04 030 916.
Supplementary European Search Report EP 92 91 9271.
International Search Report to Application No. PCT/AU92/00465.
International Preliminary Examination Report to Application No.
PCT/AU92/00465.
|
Primary Examiner: Pham; Hoa Q.
Attorney, Agent or Firm: Dressler, Goldsmith Shore & Milnamow, Ltd.
Claims
We claim:
1. A method for determining a measurement parameter of a fibrous object and
whether the object is a valid object, comprising:
(a) passing a validating energy beam through a validating interaction
volume;
(b) detecting validating outgoing energy originating from the validating
energy beam in the validating interaction volume, the detection being in
at least one validating focal plane of the validating outgoing energy with
respect to the validating interaction volume and determining a validating
parameter from the detected validating outgoing energy wherein the
validating parameter is indicative of whether an object in the validating
interaction volume is a single object in a valid measuring position and
orientation;
(c) determining from the validating parameter whether the validating
outgoing energy originated from an interaction between a fibrous object
and validating beam in the validating volume and, on determining an
object;
(d) passing a measurement energy beam through the measurement interaction
volume, said measurement interaction volume being the same as the
validating interaction volume, to interact with the object whereby at
least a part of the measurement energy beam is occluded by the fibrous
object so as to produce measurement outgoing energy in the form of a
diffraction pattern;
(e) detecting a portion of the measurement outgoing energy in at least one
measurement focal plane of the measurement outgoing energy with respect to
the measurement interaction volume, the measurement focal plane being
different from the validating focal plane, and wherein the detected
portion of said measurement outgoing energy is not so much that parameters
independent of the measurement parameter prevent determination of the
measurement parameter from the measurement outgoing energy to a required
accuracy and determining a measurement parameter to the required accuracy
from the detected measurement outgoing energy; and
(f) determining from the validating parameter whether the fibrous object is
a valid object, said object being a valid object when it is a single
object in a valid measuring position and orientation; and, on determining
a valid object, determining a first parameter of the valid fibrous object
from the measurement parameter and
determining the first parameter of the valid fibrous object as an
acceptable valid object parameter wherein the first parameter is a
diameter of the fibrous object.
2. A method for determining a measurement parameter of a valid object,
comprising:
the method of claim 1; and, on determining a valid object,
determining the measurement parameter of the valid object as an acceptable
valid object parameter.
3. A method for determining a measurement parameter of an invalid object,
comprising:
the method of claim 1; and, on determining an invalid object,
determining the measurement parameter of the invalid object as an
unacceptable valid object parameter.
4. The method of claim 1 wherein
the validating energy beam is the same as the measurement energy beam and
is a collimated light beam;
the validation interaction volume is the same as the measurement
interaction volume and is one interaction volume;
the validating parameter is the intensity from at least part of an image of
the interaction volume produced using the validating outgoing energy, the
validating outgoing energy being in the form of light; and
the measurement parameter is the intensity of at least a portion of the
measurement outgoing energy said measurement outgoing energy being a
diffraction pattern.
5. The method of claim 1 wherein
a valid fibrous object comprises a fibre selected from a group including
fibreglass fibre, hessian fibre, nylon fibre, glass fibre, polnosic fibre,
polyester fibre, abaca fibre, silk fibre, jute fibre, flax fibre,
cellulose fibre, regenerated fibre, sisal fibre, carbon fibre, stainless
steel fibre, vegetable fibre, polyolefin fibre, steel fibre, boron fibre,
copper fibre, brass fibre, teflon fibre, dacron fibre, mylar fibre,
aluminium fibre, aluminium alloy fibre, polyamide fibre, polyacrylic
fibre, nylon 66 polyacrylonitrile fibre, polyvinyl alcohol fibre, edible
vegetable fibre, inedible vegetable fibre, wood pulp fibre, cotton fibre,
animal fibre, meat fibre, sheep wool fibre, hair, human hair, goat hair,
cattle hair, yarn, wool yarn, cotton yarn, string, wire and optical fibre;
and
has a preselected length in a preselected position and orientation in the
validation and measurement interaction volume.
6. The method of claim 1 wherein
the validating energy beam is the same as the measurement energy beam and
is an expanding beam of light emerging from a pinhole illuminated by a
collimated light beam;
the validation interaction volume is the same as the measurement
interaction volume and is one interaction volume;
the validating parameter is the intensity from at least part of an image of
the interaction volume produced using the validating outgoing energy, the
validating outgoing energy being in the form of light;
the measurement parameter is the intensity of at least a portion of the
measurement outgoing energy said measurement outgoing energy being a
diffraction pattern;
a valid object comprises a fibre selected from the group consisting of a
sheep wool fibre and goat hair; and
has a preselected length in a preselected position and orientation in the
validation and measurement interaction volume and the first parameter is
the diameter of the fibre; and the method further comprises
repeating the method of claim 1 a plurality of times and determining
statistical information in respect of a plurality of the diameters of this
valid object.
7. The method of claim 1 wherein
the validating energy beam is the same as the measurement energy beam and
is a collimated light beam;
the validation interaction volume is the same as the measurement
interaction and is one interaction volume;
the validating parameter is the intensity from at least part of an image of
the interaction volume produced using the validating outgoing energy, the
validating outgoing energy being in the form of light;
the measurement parameter is the intensity of at least a portion of the
measurement outgoing energy said measurement outgoing energy being a
diffraction pattern;
a valid object comprises a fibre selected from the group consisting of a
sheep wool fibre and goat hair; and
has a preselected length in a preselected position and orientation in the
validation and measurement interaction volume and the first parameter is
the diameter of the fibre; and the method further comprises
repeating the method of claim 1 a plurality of times and determining
statistical information in respect of a plurality of the diameters of the
valid object.
8. A method for determining a diameter of a fibrous object and determining
a first parameter of an invalid object, comprising:
passing a validating energy beam through a validating interaction volume;
detecting validating outgoing energy originating from the validating energy
beam in the validating interaction volume, the detection being in at least
one validating focal plane of the validating outgoing energy with respect
to the validating interaction volume and determining a validating
parameter from the detected validating outgoing energy;
determining from the validating parameter whether the validating outgoing
energy originated from an interaction between said fibrous object and the
validating beam in the validating volume and, on determining said fibrous
object;
locating said fibrous object in a measurement interaction volume;
passing a measurement energy beam through the measurement interaction
volume to interact with said fibrous object so as to produce measurement
outgoing energy;
detecting at least a portion of the measurement outgoing energy in at least
one measurement focal plane of the measurement outgoing energy with
respect to the measurement interaction volume, the measurement focal plane
being different from the validating focal plane, and determining a
measurement parameter from the detected measurement outgoing energy; and
determining from the validating parameter whether the fibrous object is a
valid object;
determining the diameter of the fibrous object from the measurement
parameter; and, on determining an invalid object,
determining the first parameter of the invalid object as an unacceptable
valid object parameter.
9. A method for determining a measurement parameter of a valid object and
determining a measurement parameter of an invalid object, comprising:
passing a validating energy beam through a validating interaction volume;
detecting validating outgoing energy originating from the validating energy
beam in the validating interaction volume, the detection being in at least
one validating focal plane of the validating outgoing energy with respect
to the validating interaction volume and determining a validating
parameter from the detected validating outgoing energy;
determining from the validating parameter whether the validating outgoing
energy originated from an interaction between a fibrous object and the
validating beam in the validating volume and, on determining an object;
locating the fibrous object in a measurement interaction volume;
passing a measurement energy beam through the measurement interaction
volume to interact with the fibrous object so as to produce measurement
outgoing energy;
detecting at least a portion of the measurement outgoing energy in at least
one measurement focal plane of the measurement outgoing energy with
respect to the measurement interaction volume, the measurement focal plane
being different from the validating focal plane, and determining a
measurement parameter from the detected measurement outgoing energy; and
determining from the validating parameter whether the fibrous object is a
valid object; and,
(I) on determining a valid object,
determining the measurement parameter of the valid object as an acceptable
valid object parameter, wherein said measurement parameter is a diameter
of the fibrous object;
(II) on determining an invalid object,
determining the measurement parameter of the invalid object as an
unacceptable valid object parameter.
10. A method for determining a diameter of a fibrous object and determining
a measurement parameter of an invalid object, comprising:
passing a validating energy beam through a validating interaction volume;
detecting validating outgoing energy originating from the validating energy
beam in the validating interaction volume, the detection being in at least
one validating focal plane of the validating outgoing energy with respect
to the validating interaction volume and determining a validating
parameter from the detected validating outgoing energy;
determining from the validating parameter whether the validating outgoing
energy originated from an interaction between the fibrous object and the
validating beam in the validating volume and, on determining the fibrous
object;
locating the fibrous object in a measurement interaction volume;
passing a measurement energy beam through the measurement interaction
volume to interact with the fibrous object so as to produce measurement
outgoing energy;
detecting at least a portion of the measurement outgoing energy in at least
one measurement focal plane of the measurement outgoing energy with
respect to the measurement interaction volume, the measurement focal plane
being different from the validating focal plane, and determining a
measurement parameter from the detected measurement outgoing energy; and
determining from the validating parameter whether the fibrous object is a
valid object; and,
(I) on determining a valid object,
determining the diameter of the fibrous object from the measurement
parameter;
determining the diameter of the valid object as an acceptable valid object
parameter;
(II) on determining an invalid object,
determining the measurement parameter of the invalid object as an
unacceptable valid object parameter.
11. The method of any one of claims 1 or 3 to 7 wherein
the validating energy beam is the same as the measurement energy beam and
is an expanding beam of light emerging from a pinhole illuminated by a
collimated light beam;
the validation interaction volume is the same as the measurement
interaction volume and is one interaction volume;
the validating parameter is the intensity from at least part of an image of
the interaction volume produced using the validating outgoing energy, the
validating outgoing energy being in the form of light; and
the measurement parameter is the intensity of at least a portion of the
measurement outgoing energy said measurement outgoing energy being a
diffraction pattern.
12. An apparatus for determining a measurement parameter of a fibrous
object and whether the object is a valid object, comprising:
(a) a validating energy source for passing a validating energy beam through
a validating interaction volume;
(b) a validating detector for detecting validating outgoing energy
originating from the validating energy beam in the validating interaction
volume, the detection being in at least one validating focal plane of the
validating outgoing energy with respect to the validating interaction
volume and means for determining a validating parameter from the detected
validating outgoing energy operatively associated with the validating
detector, the validating parameter being a diameter of the fibrous object,
the validating detector being operatively associated with the validating
energy source wherein the validating parameter is indicative of whether
the fibrous object in the validating interaction volume is a single object
in a valid measuring position and orientation;
(c) verification means for determining from the validating parameter
whether the validating outgoing energy originated from an interaction
between the fibrous object and the validating beam in the validating
volume, the verification means being operatively associated with the
validating detector;
(d) a measurement energy source for passing a measurement energy beam
through a measurement interaction volume, said measurement interaction
volume being the same as the validating interaction volume, to interact
with the fibrous object whereby at least a part of the measurement energy
beam is occluded by the fibrous object so as to produce measurement
outgoing energy in the form of a diffraction pattern;
(e) a measurement detector for detecting a portion of the measurement
outgoing energy in at least one measurement focal plane of the measurement
outgoing energy with respect to the measurement interaction volume, the
measurement focal plane being different from the validating focal plane,
and wherein the detected portion of said measurement outgoing energy is
not so much that parameters independent of the measurement parameter
prevent determination of the measurement parameter from the measurement
outgoing energy to a required accuracy and means for determining a
measurement parameter from the detected measurement outgoing energy
operatively associated with the measurement detector, the measurement
detector being operatively associated with the measurement energy source;
and
(f) means for determining from the validating parameter whether the fibrous
object is a valid object, the means for determining being operatively
associated with the validating detector, the fibrous object being a valid
object when it is a single object in a valid measuring position and
orientation.
13. An apparatus as in claim 12 which includes:
means for determining the first parameter of the object from the
measurement parameter, operatively associated with the measurement
detector.
14. An apparatus as in claim 12 which includes:
means for determining the first parameter of the valid object from the
measurement parameter and for determining the first parameter of the valid
object as an acceptable valid object parameter, operatively associated
with the measurement detector and the means for determining from the
validating parameter whether the object is a valid object.
15. An apparatus as in claim 12 which includes:
means for determining the measurement parameter of the valid object as an
acceptable valid object parameter, operatively associated with the
measurement detector and the means for determining from the validating
parameter whether the object is a valid object.
16. An apparatus as in claim 12 which includes:
means for determining the measurement parameter of the invalid object as an
unacceptable valid object parameter, operatively associated with the
measurement detector and the means for determining from the validating
parameter whether the object is a valid object.
17. An apparatus as in claim 12 which includes:
means for determining the first parameter of the object from the
measurement parameter and for determining the first parameter of the
invalid object as an unacceptable valid object parameter, operatively
associated with the measurement detector and the means for determining
from the validating parameter whether the object is a valid object.
18. An apparatus as in claim 12 which includes:
means for determining the measurement parameter of the valid object as an
acceptable valid object parameter and for determining the measurement
parameter of the invalid object as an unacceptable valid object parameter,
operatively associated with the measurement detector and the means for
determining from the validating parameter whether the object is a valid
object.
19. An apparatus as in claim 12 which includes:
means for determining the first parameter of the object from the
measurement parameter and for determining the first parameter of the valid
object as an acceptable valid object parameter and for determining the
measurement parameter of the invalid object as an unacceptable valid
object parameter, operatively associated with the measurement detector and
the means for determining from the validating parameter whether the object
is a valid object.
20. The apparatus of claim 12 wherein
the validating energy source is the same as the measurement energy source;
the validating energy beam is the same as the measurement energy beam and
is an expanding beam of light emerging from a pinhole illuminated by a
collimated light beam;
the validation interaction volume is the same as the measurement
interaction volume and is one interaction volume; and
the validating parameter is the intensity from at least part of an image of
the interaction volume produced using the validating outgoing energy, the
validating outgoing energy being the form of light; and
the measurement parameter is the intensity of at least a portion of the
measurement outgoing energy said measurement outgoing energy being a
diffraction pattern.
21. The apparatus of claim 12 wherein
the validating energy source is the same as the measurement energy source;
the validating energy beam is the same as the measurement energy beam and
is a collimated light beam;
the validation interaction volume is the same as the measurement
interaction volume and is one interaction volume;
the validating parameter is the intensity from at least part of an image of
the interaction volume produced using the validating outgoing energy, the
validating outgoing energy being in the form of light; and
the measurement parameter is the intensity of at least a portion of the
measurement outgoing energy said measurement outgoing energy being a
diffraction pattern.
22. The apparatus of claim 12 wherein
a valid object comprises a fibre selected from a group including fibreglass
fibre, hessian fibre, nylon fibre, glass fibre, polnosic fibre, polyester
fibre, abaca fibre, silk fibre, jute fibre, flax fibre, cellulose fibre,
regenerated fibre, sisal fibre, carbon fibre, stainless steel fibre,
vegetable fibre, polyolefin fibre, steel fibre, boron fibre, copper fibre,
brass fibre, teflon fibre, dacron fibre, mylar fibre, aluminum fibre,
aluminium alloy fibre, polyamide fibre, polyacrylic fibre, nylon 66
polyacrylonitrile fibre, polyvinyl alcohol fibre, edible vegetable fibre,
inedible vegetable fibre, wood pulp fibre, cotton fibre, animal fibre,
meat fibre, sheep wool fibre, hair, human hair, goat hair, cattle hair,
yarn, wool yarn, cotton yarn, string, wire and optical fibre; and
has a preselected length in a preselected position and orientation in the
validation and measurement interaction volume.
23. The apparatus of claim 12 wherein
the validating energy source is the same as the measurement energy source;
the validating energy beam is the same as the measurement energy beam and
is an expanding beam of light emerging from a pinhole illuminated by a
collimated light beam;
the validation interaction volume is the same as the measurement
interaction volume and is one interaction volume;
the validating parameter is the intensity from at least part of an image of
the interaction volume produced using the validating outgoing energy, the
validating outgoing energy being in the form of light;
the measurement parameter is the intensity of at least a portion of the
measurement outgoing energy said measurement outgoing energy being a
diffraction pattern;
a valid object comprises a fibre selected from a group including sheep wool
fibre and goat hair; and
has a preselected length in a preselected position and orientation in the
validation and measurement interaction volume and the first parameter is
the diameter of the fibre; and the apparatus further comprises
means for determining statistical information in respect of a plurality of
the diameters of the valid object.
24. The apparatus of claim 12 wherein
the validating energy source is the same as the measurement energy source;
the validating energy beam is the same as the measurement energy beam and
is a collimated light beam;
the validation interaction volume is the same as the measurement
interaction volume and is one interaction volume;
the validating parameter is the intensity from at least part of an image of
the interaction volume produced using the validating outgoing energy, the
validating outgoing energy being in the form of light;
the measurement parameter is the intensity of at least a portion of the
measurement outgoing energy said measurement outgoing energy being a
diffraction pattern;
a valid object comprises a fibre selected from the group consisting of a
sheep wool fibre and goat hair; and
has a preselected length in a preselected position and orientation in the
validation and measurement interaction volume and the first parameter is
the diameter of the fibre; and the apparatus further comprises
means for determining statistical information in respect of a plurality of
the diameters of the valid object.
25. The apparatus of claim 12 wherein
the validating outgoing energy is light; and
further comprising a light focuser to form an image of the validating
interaction volume on the validating detector, operatively associated with
the validating source and validating detector.
26. The apparatus of claim 12 wherein
the measurement outgoing energy is light; and
further comprising a light focuser to form an image of the measurement
interaction volume on the measurement detector, operatively associated
with the measurement source and measurement detector.
27. The apparatus of claim 12 further comprising
means to pass an object through the measurement and validating interaction
volumes, operatively associated with the validating energy source,
measurement energy source and the means for locating.
28. The apparatus of any one of claims 13, 14, 17 and 19 further comprising
means for storing and retrieving the measurement parameter(s) and the
object validation and for storing the first parameter(s), operatively
associated with the measurement detector(s) and the means for determining
the first parameter(s) and the means for determining from the validating
parameter(s) whether the object is a valid object.
29. The apparatus of any one of claims 12 to 19 wherein
the validating detector comprises an array of detecting elements.
30. The apparatus of any one of claims 12 to 19 wherein
the measurement detector comprises an array of detecting elements.
31. The apparatus of any one of claims 12 to 19 wherein
the validating outgoing energy is light; and
the validating detector comprises an optical fibre coupled to a detecting
element.
32. The apparatus of any one of claims 12 to 19 wherein
the measurement outgoing energy is light; and
the measurement detector comprises an optical fibre coupled to a detecting
element.
33. An apparatus for determining at least one characteristic of a fibrous
object comprising:
a source for generating a beam of radiant energy;
an object receiving sample volume wherein at least a portion of said beam
is incident thereon and a portion of which passes therethrough and exits
therefrom;
a validating detector positioned at a first focal plane with respect to a
beam portion exiting said volume and responsive to radiant energy incident
thereon;
circuitry coupled to said detector, for determining a validating parameter,
said validating parameter being a diameter of the fibrous object;
verification circuitry, coupled to said determining circuitry, responsive
to said validating parameter for determining a source characteristic of
said incident radiation;
a measurement detector, positioned at a second focal plane with respect to
a beam portion exiting said volume and responsive to radiant energy
incident thereon;
circuitry coupled to said measurement detector for determining a
measurement parameter;
processing circuitry, coupled to said measurement parameter determining
circuitry and to said validating parameter determining circuitry, for
determining if the object exhibits the characteristic.
Description
This invention relates to methods and apparatus for determining a
measurement parameter(s) of an object and whether the object is a valid
object, for determining a first parameter(s) of a valid object, for
determining a measurement parameter(s) of a valid object, for determining
a measurement parameter(s) of an invalid object, for determining a first
parameter(s) of an object and determining a first parameter(s) of an
invalid object, for determining a measurement parameter(s) of a valid
object and determining a measurement parameter(s) of an invalid object,
for determining a measurement parameter(s) of a valid object and
determining a first parameter(s) of a valid object, for determining a
measurement parameter(s) and a first parameter(s) of a valid object and
determining a measurement parameter(s) of an invalid object, for
determining a measurement parameter(s) of a valid object and determining a
first parameter(s) of an invalid object, for determining a first
parameter(s) of a valid object and determining a measurement parameter(s)
of an invalid object, and for determining a first parameter(s) of a valid
object and determining a first parameter(s) of an invalid object.
BACKGROUND ART
A number of methods and apparatus have been developed for obtaining a
measurement of mean fibre diameter and fibre diameter distribution in a
sample containing; a plurality of wool fibres having different diameters.
Two classes of instruments for the measurement of mean fibre diameter are:
1. Those which give an estimate of average diameter only.
2. Those which also give the distribution of fibre diameters within a
sample including statistical information such as the variance of the
diameters of the sample fibres.
In recent times the information given by the distribution of wool fibre
diameter has come to be accepted as being required in some circumstances.
To accurately estimate the distribution of the fibre diameters a large
number of measurements have to be made.
A particular method for measuring mean fibre diameter and fibre diameter
distribution involves the measurements of fibre diameters in an optical
microscope using a calibrated graticule to gauge the fibre diameters. This
method is slow, tedious and prone to errors. These errors can arise from a
number of sources including the optics, the conditioning of the fibres,
and the judgment of the operators. Measurement of a few thousand fibres
using this technique takes many hours to complete.
An instrument for determining fibre diameter distribution has been proposed
by Lynch and Michie, Australian Patent No. 472,862 entitled "Optical
Shadowing Method and Apparatus for Fibre Diameter Measurement".
In the apparatus described in 472,862 a light beam traverses a transparent
measurement cell and falls on a photoelectric sensor.
Fibres dispersed and suspended in a clear liquid are caused to flow through
the measurement cell and intercept the light beam. The reduction in the
detected light intensity as a result of a fibre properly occluding the
light beam is a function of the diameter of the fibre.
The apparatus includes a split photodetector and a processor to reject
readings when a fibre end falls within the light beam. Ensuring that the
amplitude of the signal from the two detecting elements of the split
photodetector differed by less than 10%, was thought to be sufficient for
acceptance of the measurement.
Instruments manufactured according to the teaching of the Lynch and Michie
patent have been available for many years and are used to measure the
diameter distribution of wool and other fibres.
Over this period a number of deficiencies, some of which are related to the
validity of the individual fibre measurements, have become apparent.
Firstly, equal light occlusion on the two halves of the split detector is
not sufficient to guarantee the validity or otherwise of a measurement.
For example it has been observed that the diameter of some fibres varies
more than 30% in less length than the beam diameter. These fibres can give
an unequal response from the two halves of the split detector circuitry
which would in turn reject the measurement, even though the measurement
should have been accepted. Alternatively, measurements of fibres that have
not fully crossed the light beam have been observed to have been accepted
when they should have been rejected.
Secondly, the Lynch and Michie proposal assumed that the fibre snippets
would be so dilute in the carrier liquid that the probability of two
fibres being in the light beam at the same time would be negligible.
In practice, it has been found that for a typical measurement rate of 100
fibres per second the proportion of occurrence where two fibres appear in
the light beam at the same time is significant. This effect appears in the
diameter distribution graph as a second hump at double the value of the
real distribution hump. The second hump has a significant affect on the
second moment statistic, the variance.
The Lynch and Michie patent did not teach a method for rejecting the
signals representing the occurrence of two fibres measured simultaneously
in the light beam, but practical realisation of the instrument has
included an apparatus whereby signal responses with a double peak were
interpreted as representing two fibres in the beam simultaneously and were
therefore rejected.
Observations have shown that the double peak detector does not pick up all
multiple fibre events.
OBJECTS OF INVENTION
Objects of this invention are to provide methods and apparatus for
determining a measurement parameter(s) of an object and whether the object
is a valid object, for determining a first parameter(s) of a valid object,
for determining a measurement parameter(s) of a valid object, for
determining a measurement parameter(s) of an invalid object, for
determining a first parameter(s) of an object and determining a first
parameter(s) of an invalid object, for determining a measurement
parameter(s) of a valid object and determining a measurement parameter(s)
of an invalid object, for determining a measurement parameter(s) of a
valid object and determining a first parameter(s) of a valid object, for
determining a measurement parameter(s) and a first parameter(s) of a valid
object and determining a measurement parameter(s) of an invalid object,
for determining a measurement parameter(s) of a valid object and
determining a first parameter(s) of an invalid object, for determining a
first parameter(s) of a valid object and determining a measurement
parameter(s) of an invalid object, and for determining a first
parameter(s) of a valid object and determining a first parameter(s) of an
invalid object.
DISCLOSURE OF THE INVENTION
According to a first embodiment of this invention there is provided a
method for determining a measurement parameter(s) of an object and whether
the object is a valid object, comprising:
(a) passing a validating energy beam(s) through a validating interaction
volume(s);
(b) detecting validating outgoing energy originating from the validating
energy beam(s) in the validating interaction volume(s), the detection
being in at least one validating focal plane of the validating outgoing
energy with respect to the validating interaction volume(s) and
determining a validating parameter(s) from the detected validating
outgoing energy;
(c) determining from the validating parameter(s) whether the validating
outgoing energy originated from an interaction between an object and the
validating beam(s) in the validating volume(s) and, on determining an
object;
(d) locating the object in a measurement interaction volume(s);
(e) passing a measurement energy beam(s) through the measurement
interaction volume(s) to interact with the object so as to produce
measurement outgoing energy;
(f) detecting at least a portion of the measurement outgoing energy in at
least one measurement focal plane of the measurement outgoing energy with
respect to the measurement interaction volume(s), the measurement focal
plane being different from the validating focal plane, and determining a
measurement parameter(s) from the detected measurement outgoing energy;
and
(g) determining from the validating parameter(s) whether the object is a
valid object.
According to a second embodiment of this invention there is provided a
method for determining a first parameter(s) of a valid object, comprising:
the method of the first embodiment; and, on determining a valid object,
(i') determining the first parameter(s) of the valid object from the
measurement parameter(s); and
(j') determining the first parameter(s) of the valid object as an
acceptable valid object parameter(s).
According to a third embodiment of this invention there is provided a
method for determining a measurement parameter(s) of a valid object,
comprising:
the method of the first embodiment; and, on determining a valid object,
(h') determining the measurement parameter(s) of the valid object as an
acceptable valid object parameter(s).
According to a fourth embodiment of this invention there is provided a
method for determining a measurement parameter(s) of an invalid object,
comprising:
the method of the first embodiment; and, on determining an invalid object,
(h") determining the measurement parameter(s) of the invalid object as an
unacceptable valid object parameter(s).
According to a fifth embodiment of this invention there is provided a
method for determining a first parameter(s) of an object and determining a
first parameter(s) of an invalid object, comprising:
steps (a) to (g) of the first embodiment;
(i) determining the first parameter(s) of the object from the measurement
parameter(s); and, on determining an invalid object,
(j") determining the first parameter(s) of the invalid object as an
unacceptable valid object parameter(s).
According to a sixth embodiment of this invention there is provided a
method for determining a measurement parameter(s) of a valid object and
determining a measurement parameter(s) of an invalid object, comprising:
steps (a) to (g) of the first embodiment; and,
(I) on determining a valid object,
(h') determining the measurement parameter(s) of the valid object as an
acceptable valid object parameter(s);
(II) on determining an invalid object,
(h") determining the measurement parameter(s) of the invalid object as an
unacceptable valid object parameter(s).
According to a seventh embodiment of this invention there is provided a
method for determining a measurement parameter(s) of a valid object and
determining a first parameter(s) of a valid object, comprising:
steps (a) to (g) of the first embodiment; and,
on determining a valid object,
(h') determining the measurement parameter(s) of the valid object as an
acceptable valid object parameter(s);
(i') determining the first parameter(s) of the object from the measurement
parameter(s);
(j') determining the first parameter(s) of the valid object as acceptable
valid object parameter(s).
According to a eighth embodiment of this invention there is provided a
method for determining a measurement parameter(s) and a first parameter(s)
of a valid object and determining a measurement parameter(s) of an invalid
object, comprising:
steps (a) to (g) of the first embodiment; and,
(I) on determining a valid object,
(h') determining the measurement parameter(s) of the valid object as an
acceptable valid object parameter(s);
(i') determining the first parameter(s) of the object from the measurement
parameter(s);
(j') determining the first parameter(s) of the valid object as an
acceptable valid object parameter(s);
(II) on determining an invalid object,
(h") determining the measurement parameter(s) of the invalid object as an
unacceptable valid object parameter(s).
According to a ninth embodiment of this invention there is provided a
method for determining a measurement parameter(s) of a valid object and
determining a first parameter(s) of an invalid object, comprising:
steps (a) to (g) of the first embodiment; and,
(I) on determining a valid object,
(h') determining the measurement parameter(s) of the valid object as an
acceptable valid object parameter(s);
(II) on determining an invalid object,
(i") determining the first parameter(s) of the object from the measurement
parameter(s);
(j") determining the first parameter(s) of the invalid object as an
unacceptable valid object parameter(s).
According to a tenth embodiment of this invention there is provided a
method for determining a first parameter(s) of a valid object and
determining a measurement parameter(s) of an invalid object, comprising:
steps(a) to(g) of the first embodiment; and,
(I) on determining a valid object.
(i') determining the first parameter(s) of the object from the measurement
parameter(s);
(j') determining the first parameter(s) of the valid object as an
acceptable valid object parameter(s).
(II) on determining an invalid object,
(h") determining the measurement parameter(s) of the invalid object as an
unacceptable valid object parameter(s).
According to an eleventh embodiment of this invention there is provided a
method for determining a first parameter(s) of a valid object and
determining a first parameter(s) of an invalid object, comprising:
steps(a) to (g) of the first embodiment; and,
(i) determining the first parameter(s) of the object from the measurement
parameter(s);
(I) on determining a valid object,
(j') determining the first parameter(s) of the valid object as an
acceptable valid object parameter(s).
(II) on determining an invalid object,
(j") determining the first parameter(s) of the invalid object as an
unacceptable valid object parameter(s).
Generally, the method of the first embodiment further includes at least one
of the following steps in an appropriate workable sequence:
(i) determining the first parameter(s) of the object from the measurement
parameter(s);
(k) storing the measurement parameter(s) of the object;
(l) storing the first parameter(s) of the object;
(m) retrieving the measurement parameter(s) of the object;
(n) retrieving the first parameter(s) of the object;
(o) storing the validating parameter(s) of the object;
(p) retrieving the validating parameter(s) of the object;
(q) storing the object validation;
(r) retrieving the object validation;
(h') determining the measurement parameter(s) of the valid object as an
acceptable valid object parameter(s).
(i') determining the first parameter(s) of the valid object from the
measurement parameter(s);
(j') determining the first parameter(s) of the valid object as an
acceptable valid object parameter(s);
(k') storing the measurement parameter(s) of the valid object;
(l') storing the first parameter(s) of the valid object;
(m') retrieving the measurement parameter(s) of the valid object;
(n') retrieving the first parameter(s) of the valid object;
(h") determining the measurement parameter(s) of the invalid object as an
unacceptable valid object parameter(s).
(i") determining the first parameter(s) of the invalid object from the
measurement parameter(s);
(j") determining the first parameter(s) of the invalid object as an
unacceptable valid object parameter(s);
(k") storing the measurement parameter(s) of the invalid object;
(l") storing the first parameter(s) of the invalid object;
(m") retrieving the measurement parameter(s) of the invalid object;
(n") retrieving the first parameter(s) of the invalid object.
Generally, the validating energy beam(s) is the same as the measurement
energy beam(s) and is an expanding beam of light emerging from a pinhole
illuminated by a collimated light beam or is a collimated light beam;
the validation interaction volume(s) is the same as the measurement
interaction volume(s) and is one interaction volume;
the validating parameter(s) is the intensity from at least part of an image
of the interaction volume produced using the validating outgoing energy,
the validating outgoing energy being in the form of light; and
the measurement parameter(s) is the intensity of at least a portion of the
measurement outgoing energy said measurement outgoing energy being a
diffraction pattern produced by light not occluded by the object.
Typically the light beam is a laser light beam.
The methods may include the step of focussing outgoing energy originating
from the energy beams in the interaction volumes to provide at least one
image of at least a portion(s) of the interaction volumes in the focal
plane(s) which image(s) may be a virtual image(s) or a real image(s), in
focus or out of focus.
In the first to eleventh embodiments the validating and measurement
interaction volume(s) may be the same interaction volume(s), include
portions of the same interaction volume(s), or be different interaction
volume(s).
If the validating interaction volume(s) is the same as the measurement
interaction volume(s) then the step of determining that an object that
interacted with the validating energy beam(s) in the validating
interaction volume(s) to give rise to the validating outgoing energy from
which the validating parameter(s) was detected is in a measurement
interaction volume(s), may be the same as determining from the validating
parameter(s) whether the validating outgoing energy originated from an
interaction between a valid object and the validating beam(s) in the
validating volume(s).
In the first to eleventh embodiments the validating and measurement energy
beam(s) may be the same energy beam(s), include portions of the same
energy beam(s), or be different energy beam(s).
Each of the methods of the first to eleventh embodiments may be repeated a
plurality of times and may include:
determining statistical information in respect of a plurality of the
measurement parameter(s) and/or the first and/or the validating
parameter(s) and/or object validation.
The methods of the first to eleventh embodiments may further comprise:
outputting and/or discarding invalid and/or valid first parameter(s) and/or
validating parameter(s) and/or measurement parameter(s) and/or the
determination from the validating parameter(s) whether the validating
outgoing energy originated from an interaction between a valid object and
the validating beam(s) in the validating volume(s).
The method of the first to eleventh embodiments may include:
passing an object through the validating and measurement volume(s).
Generally, the validating energy beam(s) is the same as the measurement
energy beam(s) and is an expanding beam of light emerging from a pinhole
illuminated by a collimated light beam or is a collimated light beam;
the validation interaction volume(s) is the same as the measurement
interaction volume(s) and is one interaction volume;
the validating parameter(s) is the intensity from at least part of an image
of the interaction volume produced using the validating outgoing energy,
the validating outgoing energy being in the form of light;
the measurement parameter(s) is the intensity of at least a portion of the
measurement outgoing energy said measurement outgoing energy being a
diffraction pattern;
a valid object comprises a fibre selected from the group consisting of a
sheep wool fibre and goat hair; and
has a preselected length in a preselected position and orientation in the
validation and measurement interaction volume(s) and the first
parameter(s) is the diameter of the fibre.
According to a twelfth embodiment of this invention there is provided an
apparatus for determining a measurement parameter(s) of an object and
whether the object is a valid object, comprising:
(a) a validating energy source(s) for passing a validating energy beam(s)
through a validating interaction volume(s);
(b) a validating detector(s) for detecting validating outgoing energy
originating from the validating energy beam(s) in the validating
interaction volume(s), the detection being in at least one validating
focal plane of the validating outgoing energy with respect to the
validating interaction volume(s) and means for determining a validating
parameter(s) from the detected validating outgoing energy operatively
associated with the validating detector(s), the validating detector(s)
being operatively associated with the validating energy source(s);
(c) verification means for determining from the validating parameter(s)
whether the validating outgoing energy originated from an interaction
between an object and the validating beam(s) in the validating volume(s)
the verification means being operatively associated with the validating
detector(s);
(d) means for locating the object of (c) in a measurement interaction
volume(s) the means for locating being operatively associated with the
verification means;
(e) a measurement energy source(s) for passing a measurement energy beam(s)
through the measurement interaction volume(s) to interact with the object
so as to produce measurement outgoing energy;
(f) a measurement detector(s) for detecting at least a portion of the
measurement outgoing energy in at least one measurement focal plane of the
measurement outgoing energy with respect to the measurement interaction
volume(s), the measurement focal plane being different from the validating
focal plane, and means for determining a measurement parameter(s) from the
detected measurement outgoing energy operatively associated with the
measurement detector(s), the measurement detector(s) being operatively
associated with the measurement energy source(s); and
(g) means for determining from the validating parameter(s) whether the
object is a valid object, the means for determining being operatively
associated with the validating detector(s).
According to a thirteenth embodiment of this invention there is provided an
apparatus for determining a validating parameter(s) and a first
parameter(s) of an object, comprising:
the apparatus of the twelfth embodiment; and,
means for determining the first parameter(s) of the object from the
measurement parameter(s), operatively associated with the measurement
detector(s).
According to a fourteenth embodiment of this invention there is provided an
apparatus for determining a first parameter(s) of a valid object,
comprising:
the apparatus of the twelfth embodiment;
means for determining the first parameter(s) of the valid object from the
measurement parameter(s) and for determining the first parameter(s) of the
valid object as an acceptable valid object parameter(s), operatively
associated with the measurement detector(s) and the means for determining
from the validating parameter(s) whether the object is a valid object.
According to a fifteenth embodiment of this invention there is provided an
apparatus for determining a measurement parameter(s) of a valid object,
comprising:
the apparatus of the twelfth embodiment;
means for determining the measurement parameter(s) of the valid object as
an acceptable valid object parameter(s), operatively associated with the
measurement detector(s) and the means for determining from the validating
parameter(s) whether the object is a valid object.
According to a sixteenth embodiment of this invention there is provided an
apparatus for determining a measurement parameter(s) of an invalid object,
comprising:
the apparatus of the twelfth embodiment;
means for determining the measurement parameter(s) of the invalid object as
an unacceptable valid object parameter(s), operatively associated with the
measurement detector(s) and the means for determining from the validating
parameter(s) whether the object is a valid object.
According to a seventeenth embodiment of this invention there is provided
an apparatus for determining a first parameter(s) of an object and
determining a first parameter(s) of an invalid object, comprising:
the apparatus of the twelfth embodiment;
means for determining the first parameter(s) of the object from the
measurement parameter(s) and for determining the first parameter(s) of the
invalid object as an unacceptable valid object parameter(s), operatively
associated with the measurement detector(s) and the means for determining
from the validating parameter(s) whether the object is a valid object.
According to a eighteenth embodiment of this invention there is provided an
apparatus for determining a measurement parameter(s) of a valid object and
determining a measurement parameter(s) of an invalid object, comprising:
the apparatus of the twelfth embodiment;
means for determining the measurement parameter(s) of the valid object as
an acceptable valid object parameter(s) and for determining the
measurement parameter(s) of the invalid object as an unacceptable valid
object parameter(s), operatively associated with the measurement
detector(s) and the means for determining from the validating parameter(s)
whether the object is a valid object.
According to a nineteenth embodiment of this invention there is provided an
apparatus for determining a measurement parameter(s) of a valid object and
determining a first parameter(s) of a valid object, comprising:
the apparatus of the twelfth embodiment;
means for determining the measurement parameter(s) of the valid object as
an acceptable valid object parameter(s) and for determining the first
parameter(s) of the object from the measurement parameter(s) and for
determining the first parameter(s) of the valid object as acceptable valid
object parameter(s), operatively associated with the measurement
detector(s) and the means for determining from the validating parameter(s)
whether the object is a valid object.
According to a twentieth embodiment of this invention there is provided an
apparatus for determining a measurement parameter(s) and a first
parameter(s) of a valid object and determining a measurement parameter(s)
of an invalid object, comprising:
the apparatus of the twelfth embodiment;
means for determining the measurement parameter(s) of the valid object as
an acceptable valid object parameter(s) and for determining the first
parameter(s) of the object from the measurement parameter(s) and for
determining the first parameter(s) of the valid object as an acceptable
valid object parameter(s) and for determining the measurement parameter(s)
of the invalid object as an unacceptable valid object parameter(s),
operatively associated with the measurement detector(s) and the means for
determining from the validating parameter(s) whether the object is a valid
object.
According to a twenty first embodiment of this invention there is provided
an apparatus for determining a measurement parameter(s) of a valid object
and determining a first parameter(s) of an invalid object, comprising:
the apparatus of the twelfth embodiment;
means for determining the measurement parameter(s) of the valid object as
an acceptable valid object parameter(s) and for determining the first
parameter(s) of the object from the measurement parameter(s) and for
determining the first parameter(s) of the invalid object as an
unacceptable valid object parameter(s), operatively associated with the
measurement detector(s) and the means for determining from the validating
parameter(s) whether the object is a valid object.
According to a twenty second embodiment of this invention there is provided
an apparatus for determining a first parameter(s) of a valid object and
determining a measurement parameter(s) of an invalid object, comprising:
the apparatus of the twelfth embodiment;
means for determining the first parameter(s) of the object from the
measurement parameter(s) and for determining the first parameter(s) of the
valid object as an acceptable valid object parameter(s) and for
determining the measurement parameter(s) of the invalid object as an
unacceptable valid object parameter(s), operatively associated with the
measurement detector(s) and the means for determining from the validating
parameter(s) whether the object is a valid object.
According to a twenty third embodiment of this invention there is provided
an apparatus for determining a first parameter(s) of a valid object and
determining a first parameter(s) of an invalid object, comprising:
the apparatus of the twelfth embodiment;
means for determining the first parameter(s) of the object from the
measurement parameter(s) and for determining the first parameter(s) of the
valid object as an acceptable valid object parameter(s) and for
determining the first parameter(s) of the invalid object as an
unacceptable valid object parameter(s), operatively associated with the
measurement detector(s) and the means for determining from the validating
parameter(s) whether the object is a valid object.
Generally, the apparatus of the twelfth embodiment further comprises at
least one of the following items:
(i) means for determining the first parameter(s) of the object from the
measurement parameter(s) operatively associated with the measurement
detector(s);
(k) means for storing the measurement parameter(s) of the object
operatively associated with the measurement detector(s);
(l) means for storing the first parameter(s) of the object operatively
associated with the means for determining the first parameter(s);
(m) means for retrieving the measurement parameter(s) of the object
operatively associated with the means for storing the measurement
parameter(s);
(n) means for retrieving the first parameter(s) of the object operatively
associated with the means for storing the first parameter(s);
(o) means for storing the validating parameter(s) of the object operatively
associated with the validating detector(s);
(p) means for retrieving the validating parameter(s) of the object
operatively associated with the means for storing the validating
parameter(s);
(q) means for storing the object validation operatively associated with the
means for determining whether the object is a valid object;
(r) means for retrieving the object validation operatively associated with
the means for storing the object validation;
(h') means for determining the measurement parameter(s) of the valid object
as an acceptable valid object parameter(s) operatively associated with the
means for determining whether the object is a valid object and the
measurement detector(s);
(i') means for determining the first parameter(s) of the valid object from
the measurement parameter(s) operatively associated with the means for
determining whether the object is a valid object and the measurement
detector(s);
(j') means for determining the first parameter(s) of the valid object as an
acceptable valid object parameter(s) operatively associated with the means
for determining whether the object is a valid object and the means for
determining the first parameter(s) of the valid object(or the object);
(k') means for storing the measurement parameter(s) of the valid object
operatively associated with the means for determining whether the object
is a valid object and the measurement detector(s);
(l') means for storing the first parameter(s) of the valid object
operatively associated with the means for determining whether the object
is a valid object and the means for determining the first parameter(s) of
the valid object(or the object);
(m') means for retrieving the measurement parameter(s) of the valid object
operatively associated with the means for determining whether the object
is a valid object and the means for storing the measurement parameter(s)
of the valid object (or the object);
(n') means for retrieving the first parameter(s) of the valid object
operatively associated with the means for determining whether the object
is a valid object and the means for storing the first parameter(s) of the
valid object(or the object);
(h") means for determining the measurement parameter(s) of the invalid
object as an acceptable invalid object parameter(s) operatively associated
with the means for determining whether the object is a invalid object and
the measurement detector(s);
(i") means for determining the first parameter(s) of the invalid object
from the measurement parameter(s) operatively associated with the means
for determining whether the object is a invalid object and the measurement
detector(s);
(j") means for determining the first parameter(s) of the invalid object as
an acceptable invalid object parameter(s) operatively associated with the
means for determining whether the object is a invalid object and the means
for determining the first parameter(s) of the invalid object(or the
object);
(k") means for storing the measurement parameter(s) of the invalid object
operatively associated with the means for determining whether the object
is a invalid object and the measurement detector(s);
(l") means for storing the first parameter(s) of the invalid object
operatively associated with the means for determining whether the object
is a invalid object and the means for determining the first parameter(s)
of the invalid object(or the object);
(m") means for retrieving the measurement parameter(s) of the invalid
object operatively associated with the means for determining whether the
object is a invalid object and the means for storing the measurement
parameter(s) of the invalid object(or the object);
(n") means for retrieving the first parameter(s) of the invalid object
operatively associated with the means for determining whether the object
is a invalid object and the means for storing the first parameter(s) of
the invalid object (or the object).
The means for determining, storing and retrieving the measurement
parameter(s) and/or the first parameter(s) may perform such a step(s)
prior to or after the determination of the validity of an object.
Advantageously, the validating energy source(s) is the same as the
measurement energy source(s);
the validating energy beam(s) is the same as the measurement energy beam(s)
and is an expanding beam of light emerging from a pinhole illuminated by a
collimated light beam or is a collimated light beam;
the validation interaction volume(s) is the same as the measurement
interaction volume(s) and is one interaction volume; and
the validating parameter(s) is the intensity from at least part of an image
of the interaction volume produced using the validating outgoing energy,
the validating outgoing energy being in the form of light; and
the measurement parameter(s) is the intensity of at least a portion of the
measurement outgoing energy said measurement outgoing energy being a
diffraction pattern.
Generally, the validating energy source(s) is the same as the measurement
energy source(s);
the validating energy beam(s) is the same as the measurement energy beam(s)
and is an expanding beam of light emerging from a pinhole illuminated by a
collimated light beam or is a collimated light beam;
the validation interaction volume(s) is the same as the measurement
interaction volume(s) and is one interaction volume;
the validating parameter(s) is the intensity from at least part of an image
of the interaction volume produced using the validating outgoing energy,
the validating outgoing energy being in the form of light;
the measurement parameter(s) is the intensity of at least a portion of the
measurement outgoing energy said measurement outgoing energy being a
diffraction pattern;
a valid object comprises a fibre selected from the group consisting of a
sheep wool fibre and goat hair; and
has a preselected length in a preselected position and orientation in the
validation and measurement interaction volume(s) and the first
parameter(s) is the diameter of the fibre.
Typically, the apparatus further comprises
means for determining statistical information in respect of a plurality of
the diameters of the valid object(s).
Typically, the validating outgoing energy is light; and
the apparatus further comprises a light focuser to form an image of the
validating interaction volume on the validating detector(s), operatively
associated with the validating source(s) and validating detector(s).
Typically, the measurement outgoing energy is light; and
the apparatus further comprises a light focuser to form an image of the
measurement interaction volume on the measurement detector(s), operatively
associated with the measurement source(s) and measurement detector(s).
Advantageously, the apparatus of the invention may further comprise:
means to pass an object through the measurement and validating interaction
volumes, operatively associated with the validating energy source(s),
measurement energy source(s) and the means for locating.
Typically the light source is a laser.
The apparatus may include a focuser(s) for focussing outgoing energy
originating from the energy beams in the interaction volumes to provide at
least one image of at least a portion(s) of the interaction volumes in the
focal plane which image(s) may be a virtual image(s) or a real image(s),
in focus or out of focus at the validating detector(s) and/or the
measurement detector(s).
The validating and measurement means may be the same, may include common
elements or may be different from one another.
The validating and measurement energy sources may be the same, may include
common elements or may be different from one another.
The measurement parameter(s) and validating parameter(s) may be the same or
may be different from one another. If they are the same they may differ in
that they are detected at different precisions, for example. The
measurement parameter(s) and validating parameter(s) may both be used to
determine the first parameter(s) and/or the object validation(but to
different resolutions from one another).
The measurement and validating detector(s) may be the same, may include
common elements or may be different from one another.
The detection of the validating and measurement outgoing energies may take
place simultaneously, at overlapping times or at different times and/or
the measurement parameter(s) may be used to determine the validity of the
measurement and/or the validating parameter(s) may be used to determine
the first parameter(s).
The validating and measurement interaction volume(s) may be the same
interaction volume(s), include portions of the same interaction volume(s),
or be different interaction volume(s).
The validating and measurement energy beam(s) may be the same energy
beam(s), include portions of the same energy beam(s), or be different
energy beam(s).
The apparatus of the invention may further comprise:
means for outputting and/or discarding invalid and/or valid first
parameter(s) and/or validating parameter(s) and/or measurement
parameter(s) and/or the determination from the validating parameter(s)
whether the validating outgoing energy originated from an interaction
between a valid object and the validating beam(s) in the validating
volume(s), the means for outputting being operatively associated with the
means for determining the first and/or validating parameter(s) and/or the
means for storing the measurement parameter(s) and/or the first and/or
validating parameter(s) and/or the validating and/or measurement
detector(s).
The outputting may be in the form of an information signal or information
display, for example. Examples of information signals or information
displays include written text, on paper, electronic display screens (LCD
screens, electroluminescent screens, gas plasma screens, video monitors,
for example) digital or analogue electronic signals, acoustic signals,
magnetic signals, electromagnetic signals, for example.
The apparatus of the invention may include:
means for determining statistical information in respect of a plurality of
measurement and/or first and/or validating parameter(s), and/or object
validations operatively associated with the means for determining the
first and/or validating parameter(s) and/or the means for storing the
measurement parameter(s) and/or the first and/or validating parameter(s)
and/or the validating and/or measurement detector(s).
Examples of statistical information include mean, standard deviation,
coefficient of variation, variance, skewness, kurtosis, and other moments
about the mean, spline fits, line fits including linear, exponential,
logarithmic, multiple and polynomial regressions, fractal fitting, mode,
median, distribution fits including normal, gaussian, fermi, poisson,
binomial, Weibull, parabolic, frequency, probability, cumulative and top
hat distributions, data smoothing including running medians, means and
least squares, table formation such as histograms and two way contingency,
data manipulation for graphs, forecasting, probability statistics,
simulations, pattern recognition, t test, chi square test, sample size,
Wilcoxon signed-rank test, rank sum test, Kolmogorov-Smirnov test and
boundary value and limit statistics. A more detailed description of
statistical techniques is disclosed in G. E. P. Box, W. G. Hunter and J.
S. Hunter, Statistics for Experimenters, John Wiley & Sons, Inc, New York,
U.S.A., 1978, the contents of which are incorporated herein by cross
reference.
Generally, multiple focal planes of the outgoing energies are detected.
A valid object must have a measurable parameter(s) which can be validated.
Examples of such measurable parameter(s) include a valid shape, diameter,
area, chemical composition, colour, number of parts, thickness, width,
length, absorptivity, reflectivity, transmittivity, dielectric constant,
Raman scattering profile, fluorescence, surface texture or other surface
detail, position, orientation, surface tension, surface roughness, surface
profile or density, for example in the ease of a fibrous object for
example where the first parameter is diameter, for example a valid object
may be one in which a single fibre fully traverses the centre of the
validating and measurement beam(s)(which may be the same beam) in the
validating and measurement volume(s)(which may be the same volume).
The first parameter(s) may be shape, diameter, area, chemical composition,
colour, number of parts, thickness, width, length, absorptivity,
reflectivity, transmittivity, dielectric constant, Raman scattering
profile, fluorescence, surface texture or other surface detail, position,
orientation, surface tension, surface roughness, surface profile or
density, for example. In the case of a fibrous object for example the
first parameter may be diameter, for example.
A valid first parameter(s) measuring position and orientation may be when
an object fully crosses the centre of the energy beam(s) and without
another object being in the energy beam(s). The validation may be false if
there is no object in the interaction volume(s) or if there is more than
one object in the energy beam(s) in the interaction volume(s) or if the
object does not intersect the energy beam(s) fully in the interaction
volume(s) or if the object in the energy beam(s) in the interaction
volume(s) is not a single bodied object, for example.
The energy source(s) may be coherent, partially coherent or incoherent and
can provide a solid particle beam, such as a neutron, proton or electron
beam or a beam of alpha particles, acoustic waves, such as sound waves, or
electromagnetic radiation, such as gamma rays, x-rays, UV light, visible
light, infrared light or microwaves. Generally the energy source is a
source of electromagnetic radiation with a wavelength in the range of and
including far IJV to far IR.
Examples of light sources include incandescent sources, such as tungsten
filament source, vapour lamps such as halogen lamps including sodium and
iodine vapour lamps, discharge lamps such as xenon arc lamp and a Hg are
lamp, solid state light sources such as photo diodes, super radiant
diodes, light emitting diodes, laser diodes, electroluminescent light
sources, frequency doubled lasers, laser light sources including rare gas
lasers such as an argon laser, argon/krypton laser, neon laser, helium
neon laser, xenon laser and krypton laser, carbon monoxide and carbon
dioxide lasers, metal ion lasers such as cadmium, zinc, mercury or
selenium ion lasers, lead salt lasers, metal vapour lasers such as copper
and gold vapour lasers, nitrogen lasers, ruby lasers, iodine lasers,
neodymium glass and neodymium YAG lasers, dye lasers such as a dye laser
employing rhodamine, 640, Kiton Red 620 or rhodamine 590 dye, and a doped
fibre laser.
The energy source may be a pinhole energy source. The energy source may
comprise an energy fibre, the exit end of which may effectively act as a
pinhole source.
The energy beam(s) may be collimated, diverging or converging.
The energy beam(s) in the interaction volume(s) may take the form of a
diffraction pattern(s).
The outgoing energy may be transmitted and/or redirected energy.
The outgoing energy may include an interacted and/or uninteracted portion
of the energy beam(s).
The outgoing energy where it intersects the validation detector may be a
portion of the diffraction pattern resulting from the occlusion of the
energy beam(s) by a portion of an object in the interaction volume(s).
If the source is a pinhole source and the energy beam(s) is the diffraction
pattern resulting from the passage of energy through the pinhole, the
outgoing energy in a focal plane may take the form of the optical
superposition of the diffraction pattern resulting from the pinhole and
the diffraction pattern resulting from interaction between the energy
beam(s) and a portion of the object in the interaction volume(s).
The apparatus may include means to pass the object through the interaction
volume(s), the means to pass being operatively associated with the means
for locating. The means to pass may be a sample carrier such as a conveyer
strip, a sample holder on a linear or rotary stage or a fluid stream
(fluid including liquids and gases), for example. The fluid stream may be
confined by a cell which cell is used to orientate objects therein. The
interaction volume(s) may be defined by the intersection of the central
portion of the energy beam(s) and the cell. The cell may be of the type
described in Australian Patent No. 472,862 the contents of which are
incorporated heroin by cross reference and/or Australian Patent No.
599,053 the contents of which are incorporated heroin by cross reference.
The apparatus may comprise a scanner operatively associated with the energy
source(s) and/or the object and/or the sample carrier to scan the energy
beam relative to the object in the interaction volume(s). The scanner may
be a piezoelectric stack, a magnetic core/magnetic coil combination, a
mechanical vibrator, an electromechanical vibrator, a mechanical or
electromechanical scanning mechanism such as a servomotor, an acoustic
coupler electrooptic scanning means or any other suitable means.
The energy source(s) may include a first energy deflector located between
the source and the interaction volume(s) wherein a portion of the energy
beam(s) passes through the first deflector and whereby the first deflector
is operatively associated with the source to alter the shape, size,
wavelength, intensity, polarisation, phase, direction of travel or focus
of at least a portion of the energy beam(s) in the interaction volume(s).
There may be disposed in the path of the outgoing energy between the
interaction volume(s) and the validation detector and/or the measurement
detector, a second energy deflector wherein the outgoing energy passes
through the second deflector which alters the size, shape, intensity,
polarisation, phase, direction of travel, focus or wavelength, for
example. The second energy deflector may split the validating and
measurement outgoing energy.
The first and second energy deflectors may include energy focusers or
energy reflectors.
The focuser may be refractive lenses, including microscope objectives,
reflective lenses, and/or holographic optical elements. If the energy is
of a frequency other than in the range of UV to near infrared light or
other types of energies, analogous focussing elements are used in place of
the optical focussing elements.
The reflector may be a mirror or partially silvered mirror, a beam splitter
including a polarisation dependent beam splitter, energy waveguide
splitter (eg an optical fibre coupler) or a wavelength dependent beam
splitter, for example. The optical fibre coupler may be a fused biconical
taper coupler, a polished block coupler, a bottled and etched coupler or a
bulk optics type coupler with fibre entrance and exit pigtails, a planar
waveguide device based on photolithographic or ion-diffusion fabrication
techniques or other like coupler.
The object may be a fluid or solid or other of matter. Examples of objects
include mineral objects, such as diamonds and other crystals, organic and
inorganic contaminants, fibrous objects, randomly shaped objects,
spherical objects or cylindrical objects. Generally the objects are
fibrous objects or woven or twisted fibrous objects. The fibrous objects
may be synthetic fibres or natural fibres. The fibres may be fibreglass
fibres, hessian fibres, nylon fibres, glass fibres, polnosic and polyester
fibres, abaca fibres, silk fibres, jute fibres, flax and cellulose fibres
(including paper, recycled paper, corn stalks, sugar cane, wood, wood
shavings, bagasse, wood chips), regenerated fibres such as viscose, rayon,
cuprammonium rayon and cellulose acetate, sisal fibres, carbon fibres,
stainless steel fibres, vegetable fibrous material, polyolefin fibres such
as polyethylenes and polypropylene, steel fibres, boron fibres, copper
fibres, brass fibres, teflon fibres, dacron fibres, mylar fibres,
aluminium fibres, aluminium alloy fibres, polyamide fibres, polyacrylic
fibres, or absorbent fibres such as nylon 66 polyacrylonitrile, or
polyvinyl alcohol and absorbent types of polyesters or polyacrylics,
edible vegetable fibres, such as wheat fibres, or inedible vegetable
fibres, such as wood pulp or cotton fibres, animal fibres, such as meat
fibres, wool fibres such as wool fibres from sheep, hairs, such as human
hairs, goat hairs, cattle hairs, or feathers, yarns including wool and
cotton yarns, string, wire, optical fibres for example.
Typically, a valid object comprises a fibre selected from the group
consisting of a fibreglass fibre, hessian fibre, nylon fibre, glass fibre,
polnosic fibre, polyester fibre, abaca fibre, silk fibre, jute fibre, flax
fibre, cellulose fibre, regenerated fibre, sisal fibre, carbon fibre,
stainless steel fibre, vegetable fibre, polyolefin fibre, steel fibre,
boron fibre, copper fibre, brass fibre, teflon fibre, dacron fibre, mylar
fibre, aluminium fibre, aluminium alloy fibre, polyamide fibre,
polyacrylic fibre, nylon 66 polyacrylonitrile fibre, polyvinyl alcohol
fibre, edible vegetable fibre, inedible vegetable fibre, wood pulp fibre,
cotton fibre, animal fibre, meat fibre, sheep wool fibre, hair, human
hair, goat hair, cattle hair, yarn, wool yarn, cotton yarn, string, wire
and optical fibre.
Generally, a valid object has a preselected length in a preselected
position and orientation in the validation and measurement interaction
volume(s).
The measurement and/or validation detector(s) may comprise an array of
detecting elements and/or apertures. An aperture in the array may be an
energy entrance portion of an energy guide operatively associated with the
validating and/or measurement focal plane(s) to collect a portion of the
outgoing energy and guide it to the measurement and/or validation
detector(s). A detecting element in the array may be photodiode,
photomultiplier, part of a ccd array or the like.
The array may be a three dimensional array or a planar array.
The outgoing energy may be a beam and the array may be symmetric about the
central axis of the beam. The array may be a linear, square, rectangular,
circular, hexagonal, spiral, spherical, cubic or random array, for
example. Some of the apertures or detecting elements in the array may be
elongated, round, elliptical, square, rectangular, triangular, hexagonal,
rhomboid or random in shape, for example.
The apertures or detecting elements may be movable or fixed with respect to
the validating focal plane and/or the measurement focal plane and/or the
measurement and/or validating interaction volume(s).
The energy guide may be a slab waveguide. The slab waveguide can be a
single mode slab waveguide.
The energy guide can be an energy fibre.
The energy guide can be a multi mode optical fibre.
The energy guide can be a single mode optical fibre. For example, a four
micron core fibre which is single mode at a wave length of 633 nanometers
given an appropriate refractive index profile. A step index optical fibre
becomes single mode when the numerical aperture, NA, the fibre core
radius, a, and the wave length of light, .lambda., obey the relationship:
2.times..pi..times.NA.times.a/.lambda..ltoreq.2.405,
more typically
2.times..pi..times.NA.times.a/.lambda..ltoreq.0.6.
The energy guide may be a fibre bundle.
The optical fibres may include glass or plastic elements or a combination
of these.
Portions of the source and detector energy guides may be portions of the
same energy guide.
The validating detector(s) and/or the measurement detector(s) may comprise
an array of detecting elements.
When the validating outgoing energy is light the validating detector(s) may
comprise an optical fibre(s) coupled to a detecting element(s).
When the measurement outgoing energy is light the measurement detector(s)
may comprise an optical fibre(s) coupled to a detecting element(s).
The validating detector(s), the measurement detector(s), the means to
determine the first parameter(s), and/or validating means and/or means for
locating may comprise a calculator which may include optical, electrical,
optoelectronic, mechanical or magnetic elements, for example, or may
include such techniques as optical and/or electrical heterodyning,
quadrature operation, multi area detectors or phase lock loop techniques,
for example. The means for determining the first parameter(s) may log and
analyse a signal(s) from the measurement detector(s) and/or validation
detector(s) or may log and analyse the first parameter(s) and/or
validating parameter(s) and/or the measurement parameter(s) and/or the
object validation. The means for determining the first parameter(s)
typically includes a computer.
The means for locating may comprise a timer and/or a counter.
The interaction is typically one or a combination of refraction,
diffraction, reflextion, scattering, fluorescence, stimulated emission,
incandescence, shadowing, polarisation rotation, phase retardation and
other polarisation effects, occlusion, optical absorption, interference
effects, sum frequency generation, one giving rise to a diffraction
pattern, refraction, phase alteration, second, third or fourth harmonic
generation, difference frequency generation, optical bistability, self
bleaching, Raman scattering or Brillouin scattering. A nonlinear reaction
can be involved as a result of heating, refractive index change, charge
build-up or charge migration.
The first parameter(s) and the measurement parameter(s) may be the same or
may include some of the same elements or they may be different from one
another.
The validating parameter(s) and the measurement parameter(s) may be energy
intensity(including spatially or temporally dependent intensity patterns
such as images or intensity peaks or troughs as or not as a function of
time), amplitude, wavelength or frequency modulation, phase, polarisation,
wavelength, direction of travel, for example.
The apparatus of the invention may include:
a mask to mask off a portion of the validating and/or measurement and/or
validating outgoing and/or measurement outgoing beams.
For the purposes of this specification planes of focus include diffraction
planes at different distances from an object whether real or apparent(as a
result of a focuser, for example). Note that an in focus image of an
object is the diffraction plane in the plane of the object, but may be
magnified or reduced. Note also that a focuser may be used to create a
virtual as opposed to a real image.
BRIEF DESCRIPTION OF DRAWINGS
FIG. 1 schematically depicts an apparatus for determining a the mean and
standard deviation of a plurality of diameters of wool fibres, in
accordance with the invention;
FIG. 2 schematically depicts an alternative apparatus for determining a the
mean and standard deviation of a plurality of diameters of wool fibres, in
accordance with the invention;
FIG. 3 schematically depicts in detail the processor in the apparatus of
FIG. 1;
FIG. 4 schematically depicts the geometry for the apparatus of FIG. 1;
FIG. 5 schematically depicts in detail the processor/timer in the apparatus
of FIG. 1;
FIG. 6(a) is a typical reverse image of a 15 micrometer diameter wool fibre
in the plane of end 107 of apparatus 100 of FIG. 1;
FIG. 6(b) is a typical reverse image of a 15 micrometer diameter wool fibre
in the plane of detector 118 of apparatus 100 of FIG. 1;
FIGS. 7(a)-(d) show typical signals passed by comparator 113e to state
machine 113f via line 114f of processor/timer 113 of FIG. 5 of apparatus
100 of FIG. 1.
BEST MODE AND OTHER MODES FOR CARRYING OUT THE INVENTION
Referring to FIG. 1 an apparatus 100 for determining the mean and standard
deviation of a plurality of diameters of wool fibres, includes a
validating and a measurement laser light source, namely He-Ne laser 101,
and a 276 micrometer diameter pinhole 102 which form a pinhole diffraction
validating and measurement expanding laser beam which passes through a
validating and measurement interaction volume defined by the intersection
of the central diffraction spot and first diffraction ring of the
expanding laser beam and tapered cell 105 oriented not normal to the
direction of travel of the expanding laser beam. The optical path length
between the center of cell 105 and pinhole 102 is 90 mm. Polarisation
independent beam splitter 103 is operatively disposed to pinhole 102 and
laser 101 to direct a portion of the expanding laser beam to 1 mm diameter
reference detector 109 which is electrically connected to processor 110
via line 111. The optical path length between pinhole 102 and detector 109
is 208 mm. When apparatus 100 is operating wool fibres in an
isopropanol-wool slurry pass through cell 105 generally at a non-zero
degree angle to the direction of slurry flow through cell 105 to scatter,
reflect, diffract, absorb, refract and otherwise interacts with the
expanding laser beam in the interaction volume from laser 101. A detailed
description of cell 105 is contained in Australian Patent no. 599 053.
Polarisation independent beam splitter 104 and microscope objective 106
are operatively disposed with respect to laser 101, pinhole 102 and cell
105 to produce, using validating outgoing light from the interaction
volume, an in focus magnified transmission image of wool fibres in the
validating and measurement interaction volume in the plane of end 107 of
18 optical fibre ring bundle 108 comprising at end 107 a central fibre
surrounded by a 2.597 mm diameter ring of 16 plastic optical fibres each
having a 0.5 mm diameter core and a 10 micrometer thick cladding and a
single mode fibre. The optical path length between the centre of cell 105
and the front principal plane of objective 106 is 42.4 mm and the optical
path length between the back principal plane of objective 106 and end 107
is 228.2 mm so the image from the centre of cell 105 is magnified by 5.4
times at end 107. Each of the plastic fibres in bundle 108 is connected to
a photodiode detector in an the array of 17 photodiode detectors
comprising validating detector 112 for detecting the light intensity
passing through each of the fibres in bundle 108 from validating outgoing
energy originating from the validating and measurement beam in the
interaction volume. Processor/timer 113 is connected electrically to
detector 112 by line 114. Processor/timer 113 is also connected
electrically to computer 115 by line 116 and to processor 110 by line 117.
One mm diameter split detector 118 is connected electrically to processor
110 by line 119. Processor 110 is connected electrically to computer 115
by line 120. Detector 118 is operatively disposed with respect to laser
101, pinhole 102 and cell 105 to detect measurement outgoing light which
is in the form of a diffraction pattern. The optical path length between
the centre of cell 105 and detector 118 is 118 mm.
Referring to FIG. 4, which schematically depicts the geometry for apparatus
100, the observed diffraction pattern intensity at split detector 118,
resulting from pinhole 102 of diameter D and a wool fibre of diameter d at
the plane of cell 105 is given by
##EQU1##
In equations (2) to (5) A(v+p) is the illumination field amplitude in the
plane of cell 105. The equivalent normalised position on detector 118 is
given by
v=x/.sqroot.[(1+b/a)b..lambda./2], (6)
the normalised wool fibre diameter is
.DELTA.v=d.sqroot.[2(a+b)/a.b..lambda.], (7)
a is the optical path length between from pinhole 102 and the centre of
cell 105, b is the optical path length between the centre of cell 105 and
detector 118 and .lambda. is the wavelength of the light from laser 101.
As pinhole 102 is substantially uniformly illuminated by laser light from
laser 101, the illumination field amplitude at the plane of the centre of
cell 105 is circularly symmetric and is given by
A(x,y)=2 J.sub.1 (z)/z (8)
where J.sub.1 (z) is the first order Bessel function of the first kind and
z=(.pi..D/(a+b).lambda.)..sqroot.(x.sup.2 +y.sup.2) (9)
To calculate the diffraction pattern intensity I(v).vertline..sub.y=y of
equation (1), along any off-axis line y=y, equation (8) is used to
calculate the Fraunhofer field amplitude appearing in equations (2)-(5).
In order to obtain geometrically similar configurations of apparatus 100
for different optical systems, the diffraction pattern at detector 118
must scale identically with the change in detector size for the two
configurations for any given wool fibre. If the radius of detector 118 for
the new apparatus 100 (denoted by dashed variables) is related to the old
detector 118 radius R by
R'=kR (10)
then to get geometric similarity
b'=kb (11)
a'=k.b/[(1+b/a)k-1] (12)
D'/D=(a'+b')/(a+b).k (13)
Equations (10), (11), (12) and (13) thus define a new apparatus 100, which
is geometrically similar to the old and thus responds in exactly the same
way when a wool fibre passes through the interaction volume. For example,
suppose apparatus 100 with detector 118 of radius R=0.5 mm, D=276.5
micrometers and with (a,b)=(90,118) mm is replaced with a new detector 118
of radius R'=1 mm. The scaling factor is now k=2 and the new cell 105 and
detector 118 planes must be located at (a',b')=(65,235) mm, while the new
pinhole 102 diameter is D'=200 micrometers, for the new apparatus 100 to
have the same response as the old one.
For the two geometries outlined above, there is an apparent change in wool
fibre diameter with the position of the wool fibre along the axis of the
expanding laser beam. Thus, because cell 105 has a finite width, typically
2 mm, there is an uncertainty in the measured diameter. This uncertainty
is typically +/-1.9% for a 30 micron fibre. However, the apparatus of FIG.
1 may be rescaled so that there is no substantial apparent diameter change
with axial position of wool fibres along the axis of the expanding laser
beam. This can be done by making a=b or a and b tend to infinity or R tend
to 0. Thus, for an arrangement that is geometrically similar to the two
described above, one might put a'=b'=101.9 mm, D'=313.3 micrometers and
R'=0.434 mm.
If a substantial amount of interacted light is collected by detector 118,
then diameter independent parameters such as wool fibre medulation and
colour as well as position and orientation, for example may affect the
diameter determination and thus the accuracy of the measurement. Thus in
apparatus 100, detector 118 is placed with respect to cell 105 so as to
not collect so much light from the interaction volume that has interacted
with a wool fibre in cell 105 to prevent determination of the diameter of
the wool fibre to within the required accuracy. Detector 118 may be placed
closer to cell 105, at the expense of accuracy, but for optimum accuracy
should be positioned as far as possible from cell 105 to minimise effects
from diameter independent parameters on the wool fibre diameter
determination. Because of the nature of the expanding beam from pinhole
102, there is a practical limitation on the upper limit of separation
between cell 105 and detector 108. A alternative practical apparatus for
measuring fibre diameter independent of wool fibre diameter independent
parameters, in which the measurement detector is located at an effective
infinite distance from the interaction volume is described below with
reference to FIG. 2.
End 107 is centred in the image of the pinhole diffraction in the
interaction volume by maximising the light intensity collected by the
central fibre. The image of the pinhole diffraction in the interaction
volume is bought into focus at end 107 by positioning end 107 so that the
light intensity signal collected by the single mode fibre in bundle 108
substantially approximates a top hat profile when a wool fibre passes
through cell 105. Generally the fibres in the ring at end 107 are packed
closely to one another to minimise the separations between them. The
magnification of the interaction volume at end 107 is such that the 16 0.5
mm optical fibres in the ring of bundle 108 at end 107 are located just
outside the first minimum of the pinhole diffraction pattern of the image
at end 107 to capture light from the first diffraction ring. If different
diameter optical fibres are chosen or the number of fibres in the ring is
changed, for example, the position of objective 106 with respect to cell
105 and end 107 is adjusted such that the optical fibres in the ring of
bundle 108 at end 107 are located just outside the first minimum of the
pinhole diffraction pattern of the image at end 107.
Since the image of wool fibres in the interaction volume at end 107 is in
focus, information about the position and orientation of the wool fibres
is readily obtainable from the image. If end 107 is moved from the
position of the in focus image of the interaction volume the position and
orientation of the wool fibres may be less readily obtainable.
As depicted schematically in FIG. 5, processor/timer 113 comprises current
to voltage converter 113a electrically connected to detector 112 by line
114 and to amplifier 113b by line 114a. Amplifier 113b is electrically
connected to three pole butterworth filter 113c via line 114b and analogue
divider 113d by line 114d. Analogue divider 113d is also electrically
connected to comparator 113e by line 114e and filter 113c via line 114c.
Comparator 113e is electrically connected to state machine 113f via line
114f. State machine 113f is identified as a means for locating for
determining that the wool fibre that interacted with the expanding laser
beam in the interaction volume to give rise to validating outgoing energy
is the same wool fibre that gave rise to the measurement outgoing light
for the current measurement. State machine 113f is electrically connected
to timer 113g via line 114g, countdown timer 113h via line 114h, magnitude
comparator 113j via line 114i, multi storage device 113k via line 114k,
computer 115 via line 116a and line 116 and processor 110 via line 117.
Multistorage device 113k is electrically connected to computer 115 by line
116.
As depicted schematically in FIG. 3, processor 110 comprises
amplifier/divider/offsetter 110a electrically connected to detector 109 by
line 111, detector 118 by line 119, calculator 110f by line 119g and
scaler/inverter 110b by line 119a. Scaler inverter 110b is electrically
connected to threshold detector 110c by line 119c and peak detector 110d
by line 119b. Threshold detector 110c is electrically connected to
processor/timer 113 by line 117, computer 115 by line 120a and line 120,
peak counter 110e by line 119d and peak valid storage 110h by line 119e.
Peak detector 110d is electrically connected to processor/timer 113 via
lines 117a and 117, peak counter 110e by line 119f, calculator 110f by
line 119j and measurement storage 110g by line 119h. Peak counter 110e is
electrically connected to computer 115 by lines 120b and 120, calculator
110f is electrically connected to peak valid storage 110h by line 119i,
peak valid storage 110h is electrically connected to computer 115 by lines
120c and 120 and measurement storage 110g is electrically connected to
computer 115 by tines 120d and 120.
In operation, a method for determining the mean and standard deviation of a
plurality of diameters of wool fibres, includes passing a validating and
measurement laser beam from laser 101 through pinhole 102 and via splitter
103 to form a pinhole diffraction pattern in the interaction volume in
cell 105 and a reference pinhole diffraction pattern in the plane of
reference detector 109 which detects the intensity of the reference
pinhole diffraction pattern to produce a reference signal. The reference
signal from detector 109 is passed to processor 110 via line 111 where it
is amplified by amplifier/divider/offsetter 110a to produce an amplified
reference signal. The periphery of detector 109 is in about the same
position as the first minimum of the reference pinhole diffraction
pattern. In the event that there is no wool fibre in the interaction
volume, a baseline pinhole diffraction pattern is formed in the plane of
detector 118 which is detected by detector 118 to produce two baseline
signals, designated baseline signals Ab and Bb. The baseline signals from
the top and bottom halves of detector 118 are separately passed to
processor 110 by line 119, amplified and divided by the amplified
reference signal, obtained at the same time, by
amplifier/divider/offsetter 110a, to produce normalised baseline signals
Abn and Bbn. The periphery of detector 118 is in about the same position
as the first minimum of the baseline pinhole diffraction pattern. The sum
of the normalised baseline signals Abn+Bbn is offset to zero by the amount
BL by amplifier/divider/offsetter 110a. A wool fibre in the
isopropanol-wool slurry is passed through the interaction volume to
produce measurement outgoing light which is in the form of a diffraction
pattern comprising the optical superposition of the pinhole diffraction
pattern and the diffraction pattern produced by the interaction of the
wool fibre and the expanding laser beam in the interaction volume, the
measurement outgoing light passing through splitter 104 and being detected
by detector 118 to produce two measurement signals from the top and bottom
halves of split detector 118, designated measurement signals Am and Bm.
The measurement signals from detector 118 are separately passed to
processor 110 by line 119, amplified and divided by the amplified
reference signal, obtained at the same time, to produce normalised
measurement signals Amn and Bmn which are made available to calculator
110f via line 119g.
The sum of the normalised measurement signals Amn+Bmn is offset by BL by
amplifier/divider/offsetter 110a and passed to scaler/inverter 110b via
line 119a. Scaler/inverter 110b scales and inverts the signal to produce a
measurement signal M where the scaling allows M to remain within the
dynamic range of processor 110 for the largest diameter fibre to be
measured corresponding to a largest allowed measurement signal Mm. The
value M is passed to threshold detector 110c via line 119c and peak
detector 110d via line 119b.
When threshold detector determines that the measurement signal M exceeds a
threshold of typically 1%-10% of Mm, an above threshold signal is passed
to processor/timer 113 via line 117, a peak valid signal Vp in peak valid
storage 110h is set to "FALSE" via line 119e and peak counter 110e is set
to zero via line 119d. As the wool fibre passes through the interaction
volume, measurement signal M passes through a maximum due to the occlusion
of the expanding laser beam in the interaction volume by the wool fibre
which maximum is peak detected by peak detector 110d, typically within 100
microseconds, more typically within 5 microseconds of the peak, upon which
peak counter 110e is incremented via line 119f, a peak detect signal is
sent to processor/timer 113 via lines 117a and 117, the maximum value Mp
of measurement signal M is passed to measurement storage 110g via line
119h, measurement storage 110g stores Mp, the values Amn and Bmn are
accepted by calculator 110f from amplifier/divider/offsetter 110a via line
119g as directed by peak detector 110d via line 119j, calculator 110f
calculates result .vertline.(Amn-Bmn).vertline., which value may be
indicative of whether the wool fibre fully traversed the interaction
volume at the time of the peak. If the result is less than typically 10%,
more typically 3% of the value of Mp, calculator 110f sets the peak valid
signal Vp in peak valid storage 110h to "TRUE" via line 119i. If peak
detector 110d detects a second peak in measurement signal M while M
remains above threshold, peak counter 110e is incremented a second time
via line 119f.
When threshold detector 110c detects that the measurement signal M falls
below threshold, it sends a data available signal to computer 115 via
lines 120a arid 120 upon which computer 115 reads the peak value of the
measurement signal Mp stored in measurement storage 110g via lines 120d
and 120, the peak valid signal Vp stored in peak valid storage 110 via
lines 120c and 120 and the value stored in peak counter 110e via lines
120b and 120.
Validating outgoing light from the interaction volume is deflected by
splitter 104 and focussed by objective 106 to produce an in focus
magnified transmission image of the wool fibre in the interaction volume
in the plane of end 107 of bundle 108. Light falling on the cores of
fibres in bundle 108 at end 107 is guided to the array of 17 photodiode
detectors of detector 112. Each of the 17 photodiode detectors detects the
intensity of light guided by its corresponding fibre in bundle 108 to
produce an output signal which is fed to current to voltage converter 113a
via line 114. Converter 113a produces output voltages proportional to each
of the light intensity detected by the corresponding photodiodes of
detector 112. Each output voltage is passed to amplifier 113b via line
114a. Amplifier 113b amplifies and limits the bandwidth of each output
voltage to produce amplified signals which are passed to the inputs of
three pole butterworth filters 113c via line 114b and the numerator input
of analogue dividers 113d via line 114d. Filter 113c generates low
frequency (substantially DC) signals that track the baseline intensities
detected by the corresponding photodiodes in detector 112. The output of
each butterworth filter in falter 113c is passed to the denominator input
of analogue dividers 113d via line 114c. The function of each analogue
divider in divider 113d is to normalise each signal detected in detector
112 so that each of these signals can be compared to a common voltage
reference in comparator 113e. Thus the normalisation process carried out
by circuits 113a, 113b, 113c and 113d allows for variations between fibres
in bundle 108. If this was not done fibre bundle 108 would be extremely
difficult and costly to manufacture and mount. The normalised output of
each analogue divider in divider 113d is fed to comparator 113e via line
113e. Comparator 113e compares the normalised output signal levels from
divider 113d via line 114e with a voltage reference to produce a 17 bit
binary data word representative of the image focussed onto the fibres at
end 107.
The binary word is passed from circuit 113e to a change detection circuit,
comprising state machine 113f electrically connected to magnitude
comparator 11L3j via line 114i. The function of the change detection
circuit is to detect and latch any change from the current binary word
passed from comparator 113e via line 114f which occurs whenever there is a
significant change in the image focussed by lens 106 on end 107.
Before an above threshold signal is fed to state machine 113f, via line
117, computer 115 enables state machine 113f via lines 116 and 116a and
state machine 113f resets a memory storage pointer in multi storage
circuit 113k, via line 114k to the beginning of storage circuit 113k.
State machine 113f begins the data gathering process when an above
threshold signal is received from processor 110 via line 117. At the start
of the data gathering process timer 113g is reset by state machine 113f
via line 114g and begins counting and a busy flag is set in state machine
113f which busy flag can be monitored by computer 115 via lines 116a and
116. During the data gathering process, state machine 113f stores the
first binary word as a binary value in an input register. The contents of
this register are compared to the current binary word using magnitude
comparator 113j and line 114i. State machine 113f detects an inequality in
comparator 113j via line 114i and assembles the change in the data word
from comparator 113e, along with the time read from timer 113g via line
114g, sends it to multi storage circuit 113k via line 114k, increments the
memory storage pointer in multi storage circuit 113k, via line 114k and
stores the new word in the input register which removes the inequality in
magnitude comparator 113j. When the peak detect signal is received by
state machine 113f from processor 110 via line 117, countdown timer 113h
is started via line 114h. The countdown timer typically runs down in 60
micro seconds, which is detected by state machine 113f via line 114h upon
which a last data word from comparator 113e via line 114f and
corresponding time from timer 113g via line 114g is assembled by state
machine 113f and sent to multistorage 113k via line 114k, the data
gathering process is stopped and the busy flag is cleared.
Computer 115 monitors the data busy flag from state machine 113f via lines
116 and 116a to determine whether data is available for reading and
processing. If computer 115 receives the data available signal from
threshold detector 110c via lines 120a and 120, it reads the maximum value
of the measurement signal Mp from measurement storage 110g via lines 120d
and 120, the peak valid signal Vp from peak valid storage 110h via lines
120c and 120 and the value stored in peak counter 110e via lines 120b and
120. Computer 115 then reads the data words and times stored in multi
storage 113k via line 116 in reverse order, monitoring the times, until
the time monitored is less than a calculated value. The calculated value
is a predetermined amount, typically 120 microseconds, less than the first
time stamp read in by computer 115. For example, if the data gathering
process was stopped at a time stamp of 160 microseconds, computer 115
would typically stop reading data when the time stamp monitored was less
than 40 microseconds.
After reading in the data, computer 115 determines from the value of the
peak valid signal Vp and the number of counts stored in the peak counter
whether one wool fibre may have completely spanned the interaction volume
to give rise to the maximum value of the measurement signal Mp. If so
computer 115 confirms, from the data words read in, whether one wool fibre
completely spanned the interaction volume about the time Mp was determined
and stored. If the confirmation is true, computer 115 calculates the
diameter of the wool fibre from Mp using a calibration look up table and
stores it in its memory.
Apparatus 100 repeats the above procedure and thereby determines from
resultant stored wool fibre diameters the mean and standard deviation.
A typical reverse image of a 15 micrometer diameter wool fibre in the plane
of end 107 is depicted in FIG. 6(a). A typical reverse image of a 15
micrometer diameter wool fibre in the plane of detector 118 is depicted in
FIG. 6(b). Note that the image of FIG. 6(a) shows features position,
orientation, medulation and colour of the wool fibre whereas the image of
FIG. 6(b) does not distinguish such features. FIGS. 7(a)-(d) show typical
signals passed by comparator 113e to state machine 113f via line 114f.
FIG. 7(a) results from a valid wool fibre, that is, a wool fibre in a
valid position and orientation that completely crosses the interaction
volume such as the wool fibre depicted in FIG. 6(a). FIG. 7(b) results
from an invalid object, namely a wool fragment that does not completely
cross the interaction volume, passing through the interaction volume. FIG.
7(c) results from an invalid object, namely two wool fibres that pass
through the interaction volume simultaneously. FIG. 7(d) results from an
invalid object, namely a wool fibre that does not completely cross the
interaction volume, passing through the interaction volume.
Referring to FIG. 2 an apparatus 200 for determining the mean and standard
deviation of a plurality of diameters of wool fibres, includes a
validating and measurement optically isolated laser diode 201 which
injects validating and measurement laser light into the core of single
mode fibre 202. Fibre 202 is optically connected to single mode coupler
209 having ports 203, 204, 205 and 206. Port 205 of coupler 209 is
optically connected to single mode fibre 207 having exit end 208. Port 204
of coupler 209 is optically connected to photodiode 211 by fibre 210.
Photodiode 211 is electrically connected to laser diode power supply 213
by line 212. Supply 213 is electrically connected to laser 201 by line
214. Port 206 of coupler 209 is optically connected to measurement photo
diode 216 by fibre 215. Diode 216 is electrically connected to computer
218 by line 217. Collimating lens 219 collimates validating and
measurement laser light emerging from the core of fibre 207 at end 208 to
form a collimated validating and measurement laser beam typically about
350 micrometers in diameter having an approximately gaussian intensity
profile. The collimated laser beam passes through a validating and
measurement interaction volume defined by the intersection of the beam and
tapered cell 220 which is oriented not normal to the direction of travel
of the collimated beam. A detailed description of cell 220 is contained in
Australian Patent no. 599 053. When apparatus 200 is operating wool fibres
in an isopropanol slurry pass through cell 220 generally at a non-zero
degree angle to the direction of slurry flow through cell 220 to scatter,
reflect, diffract, absorb, refract and otherwise interact with the
collimated beam. Partial mirror 221 reflects measurement outgoing light
from the interaction volume, a portion of which is reinjected into end 208
of fibre 207 to be detected by diode 216. Partial mirror 221 transmits
validating outgoing light from the interaction volume. Lens 222 is
operatively disposed with respect to end 208, lens 219 and cell 220 to
produce, using validating outgoing light transmitted by partial mirror
221, a highly visible diffraction pattern from wool fibres in the
interaction volume in the plane of end 223 of 12 400 micrometer glass
cored 12.5 micrometer thick plastic clad fibre bundle 224 comprising at
end 223 a close packed circularly symmetric core configuration. Bundle 224
is optically connected to validating detector and neural network 225 which
is electrically connected to computer 218 by line 226. Sample carrier 229
is mechanically attached to mechanical stage 228 which is electrically
connected to computer 218 by line 227.
In operation, a method for determining the mean and standard deviation of a
plurality of diameters of wool fibres, includes guiding validating and
measurement laser light from diode 201 to end 208, via fibre 202, ports
203 and 205 of coupler 209 and fibre 207, from which it emerges with a
numerical aperture of typically 0.1. Lens 219 collimates the validating
and measurement light emerging from end 208 to form a collimated
validating and measurement beam which passes through cell 220. In the
event that there is no wool fibre in the interaction volume, the
collimated beam passes through cell 220 and is partially reflected as
uninteracted measurement light by partial mirror 221 back through cell
220. The uninteracted measurement light, still collimated, is focussed by
lens 219 and injected into the core of fibre 207 at end 208 and enters
coupler 209 via fibre 207 and port 205. A portion of the uninteracted
measurement light entering coupler 209 leaves coupler 209 by port 206 to
be guided by fibre 215 to diode 216 where it is detected to produce a
baseline signal Mb which is fed to computer 218 via line 217. A wool fibre
in the isopropanol-wool slurry is passed through the interaction volume to
partially occlude the collimated validating and measurement beam, thereby
producing a validating and measurement outgoing light beam. A portion of
the outgoing light is reflected by partial mirror 221 back through cell
220 where it again interacts with the wool fibre to form the measurement
outgoing light beam. A portion of the measurement outgoing light beam is
injected into the core of fibre 207 at end 208 a portion of which is
guided to diode 216 via fibre 207, ports 205 and 206 of coupler 209 and
fibre 215 where it is detected to produce a measurement signal Mm which is
fed to computer 218 via line 217. Because of the geometry of the core at
end 208 of fibre 207, lens 219 and partial mirror 221, validating and
measurement light source 201 is effectively at infinity and measurement
photodiode 216 is effectively at infinity. Therefore, measurement signal
Mm is substantially independent of wool fibre diameter independent
parameters, such as axial position along the collimated validating and
measurement beam, fibre medcuation and fibre colour, and when a single
wool fibre completely crosses the collimated validating and measurement
beam in the interaction volume and is centred in the collimated validating
and measurement beam, the signal Mm will depend almost solely on the
diameter of the fibre. (Note that there are some minor orientation effects
due to the polarisation of the collimated validating and measurement
beam.) When Mm passes through a minimum, computer 218 interrupts its
current task, stores the minimum Mmm, the minimum time at which the
minimum occurred and the last baseline signal Mb in temporary memory.
The optical power of the laser light injected into the core of fibre 202 by
laser 201 is maintained at a constant level by feedback control as
follows. A predetermined amount of the light injected into the core of
fibre 202 by laser 201 is guided to photodiode 211, via fibre 202, ports
203 and 204 of coupler 209 and fibre 210, which detects the light level
and produces a light level signal which is proportional to the light level
detected by diode 211. The light level signal is passed to supply 213 via
line 212. Supply 213 adjusts the current fed to diode 201 via line 214 to
keep the light level signal constant at some predetermined value.
The portion of the validating and measurement outgoing light beam that
passes through partial minor 221 as validating outgoing light is focussed
by lens 222 to form a highly visible diffraction pattern at end 223 of
bundle 224. A portion of the highly visible diffraction pattern enters the
cores of the fibres in bundle 224 at end 223 to be guided to and detected
by validating detector and neural network 225. Validating detector and
neural network 225 has previously been `taught` to recognise the time at
which a single wool fibre completely crosses the collimated validating and
measurement beam in the interaction volume and is centred in the
collimated validating and measurement beam. When validating detector and
neural network 225 encounters such a signal, it passes a true validation
signal to computer 218 via line 226 together with the validation true time
at which the validation detector and neural network received the
corresponding validation outgoing light via bundle 224. Computer 218 then
interrupts its current task and stores the validation true time and
increments a valid fibre counter.
When it is not busy storing measurement and validation signals, computer
218 matches each validation true time with the corresponding minimum time,
calculates the occlusion percentage Oc from the corresponding minimum Mmm
and baseline signal Mb using the formula Oc=100 (1-Mmm/Mb). The fibre
diameter is then determined from the occlusion percentage using a
calibration curve, the obtaining of which will be described below, and
stores the fibre diameter in permanent memory. Minimum, baseline signals
and minimum times that don't correspond closely with validation true times
are discarded. Validation true times that don't correspond closely with
minimum times are discarded and for each validation true time discard, the
valid fibre counter is decremented.
The above process is repeated until the valid fibre counter reaches a
predetermined amount, typically 1,000 to 10,000, at which time computer
218 matches the remaining minimum times and validation true times and
determines and stores the corresponding fibre diameters in permanent
memory. Once all of the fibre diameters have been stored in permanent
memory, computer 218 determines from the permanently stored wool fibre
diameters the mean and standard deviation.
The calibration curve is obtained as follows. A calibration sample with a
range of typically wire fibres having known diameters typically in the
range of 5 micrometers to 200 micrometers is placed on sample carrier 229.
Computer 218 then directs mechanical stage 228, via line 227, to pass the
calibration sample through the collimated validating and measurement beam.
The minimum Mmm resulting from the passage of each fibre in the
calibration sample through the collimated validating and measurement beam,
together with the baseline signal Mb accepted by computer 218 between each
accepted Mmm signal, is stored by computer 218 and each minimum Mmm is
matched with the corresponding known diameter. This process is repeated a
number of times, typically in excess of 10 times, and the average
occlusion percentage Oc determined for each calibration fibre. A
calibration curve is then fitted to the occlusion percentages and known
diameters and the calibration curve is stored by computer 218.
In an alternative mode of operation apparatus 200 determines the mean and
standard deviation as follows. A sample comprising wool fibres of unknown
diameter are placed on sample carrier 229 and passed through the
collimated validating and measurement beam and the mean and standard
deviation of the diameters of the fibres in the sample determined as
described above. In this instance, the validating and measurement
interaction volume is defined by the intersection of the sample on the
sample carrier and the collimated validating and measurement beam when the
sample is passed through the beam. Since the highly visible diffraction
pattern produced by the wool fibres and lens 222 on end 223 of bundle 224
will be different to that described above, the algorithm used by
validating detector and neural network 225 will also be different.
INDUSTRIAL APPLICABILITY
The methods and apparatus of the invention may be utilised to determine a
first parameter(s) of a valid object, such as shape, diameter, area,
chemical composition, colour, number of parts, thickness, width, length,
absorptivity, reflectivity, transmittivity, dielectric constant, Raman
scattering profile, fluorescence, surface texture or other surface detail,
position, orientation, surface tension, surface roughness, surface profile
or density, for example. In the case of a fibrous object for example the
first parameter may be diameter, for example. The measurements may be
readily performed on a plurality of objects and statistical information
readily determined from the measurements.
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